@tuxlife so, in that file drivers/video/coreboot.c you see function save_vesa_mode, which i think is it
it's reading edid to get the timings and such. then later, the actual init is done.
it is in save_vesa_mode() where you want to look
./mk -f u-boot x86_64
do that in lbmk. and then you can open the file under src/u-boot/x86_64
and you can basically just mess with it.
please delete elf/u-boot/ whenever you want to re-build with a change you make. it must be removed manually before rebuild